Abstract：
Listeria monocytogenes is an opportunistic foodborne pathogen. It can resist stress conditions by adapting through the production of biofilms, which represents a serious problem for the food industry. It is classified into 14 serotypes, although only four (1/2a, 1/2b, 1/2c, and 4b) account for 89.0-98.0% of listeriosis cases worldwide. The objective of this study was to detect and serotype L.monocytogenes isolated from different food matrices from processing plants in Argentina. In the period 2016-2021, 1832 samples (meat, ready-to-eat foods, ice cream, dairy foods, and frozen vegetables) were analyzed, of which 226 (12.34%) isolates compatible with L.monocytogenes were detected. At the same time, environmental and surface samplings were performed in processing plants for ready-to-eat foods, sausages and dairy products, where environmental contamination with L.monocytogenes was detected in numerous critical points of the process, yielding a positivity rate of 22.7%. The molecular analysis of serogroups was performed, where it was observed that serogroup IIb was the most frequent with 66.5% (n=107), and in descending order IIc with 22.3% (n=36), and IIa (n=9) and IVb (n=9) with 5.6%. The serogroup mostly isolated in environmental monitoring was IIb. This work highlights the importance of the detection and serotyping of L.monocytogenes for taking actionable measures and identifying outbreaks, and is the first study in Argentina to describe an extensive study in food matrices.
摘要：
单核细胞增生李斯特菌是一种机会性食源性病原体。它可以通过生物膜的产生来适应压力条件，这对食品工业来说是一个严重的问题。它分为14种血清型，虽然只有四个(1/2a，1/2b,1/2c,和4b）占全球李斯特菌病病例的89.0-98.0％。这项研究的目的是检测和血清型从阿根廷加工厂的不同食物基质中分离出的单核细胞增多菌。在2016-2021年期间，1832个样本(肉类，即食食品,冰淇淋,乳制品,和冷冻蔬菜)进行了分析，其中检测到226株(12.34%)与单核细胞增生利斯特菌相容的分离株。同时,在即食食品加工厂进行环境和表面采样，香肠和奶制品,在该过程的许多关键点中检测到单核细胞增生性菌的环境污染，阳性率为22.7%。进行血清群的分子分析，其中观察到血清群IIb最常见，为66.5％（n=107），按降序排列IIc，22.3%(n=36)，IIa(n=9)和IVb(n=9)占5.6%。在环境监测中最分离的血清群是IIb。这项工作强调了检测和血清分型单核细胞增多性弧菌对于采取可行措施和识别疫情的重要性，这是阿根廷第一个描述食物基质广泛研究的研究。
